package org.goobs.gui;

/**
 THIS PROGRAM IS PROVIDED "AS IS" WITHOUT ANY WARRANTIES (OR CONDITIONS),
 EXPRESS OR IMPLIED WITH RESPECT TO THE PROGRAM, INCLUDING THE IMPLIED WARRANTIES (OR CONDITIONS)
 OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK ARISING OUT OF USE OR
 PERFORMANCE OF THE PROGRAM AND DOCUMENTATION REMAINS WITH THE USER.
 */
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Insets;
import java.awt.LayoutManager;

/**
 * 
 * A vertical layout manager similar to java.awt.FlowLayout. Like FlowLayout
 * components do not expand to fill available space except when the horizontal
 * alignment is <code>BOTH</code> in which case components are stretched
 * horizontally. Unlike FlowLayout, components will not wrap to form another
 * column if there isn't enough space vertically. VerticalLayout can optionally
 * anchor components to the top or bottom of the display area or center them
 * between the top and bottom.
 * 
 * Revision date 12th July 2001
 * 
 * @author Colin Mummery e-mail: colin_mummery@yahoo.com
 *         Homepage:www.kagi.com/equitysoft - Based on 'FlexLayout' in Java
 *         class libraries Vol 2 Chan/Lee Addison-Wesley 1998
 */

public class VerticalLayout implements LayoutManager {

	/**
	 * The horizontal alignment constant that designates centering. Also used to
	 * designate center anchoring.
	 */
	public final static int CENTER = 0;
	/**
	 * The horizontal alignment constant that designates right justification.
	 */
	public final static int RIGHT = 1;
	/**
	 * The horizontal alignment constant that designates left justification.
	 */
	public final static int LEFT = 2;
	/**
	 * The horizontal alignment constant that designates stretching the
	 * component horizontally.
	 */
	public final static int BOTH = 3;

	/**
	 * The anchoring constant that designates anchoring to the top of the
	 * display area
	 */
	public final static int TOP = 1;
	/**
	 * The anchoring constant that designates anchoring to the bottom of the
	 * display area
	 */
	public final static int BOTTOM = 2;
	private final int vgap; // the vertical vgap between components...defaults
	// to 5
	private final int alignment; // LEFT, RIGHT, CENTER or BOTH...how the
	// components are justified
	private final int anchor; // TOP, BOTTOM or CENTER ...where are the

	// Constructors
	/**
	 * Constructs an instance of VerticalLayout with a vertical vgap of 5
	 * pixels, horizontal centering and anchored to the top of the display area.
	 */
	public VerticalLayout() {
		this(5, CENTER, TOP);
	}

	/**
	 * Constructs a VerticalLayout instance with horizontal centering, anchored
	 * to the top with the specified vgap
	 * 
	 * @param vgap
	 *            An int value indicating the vertical seperation of the
	 *            components
	 */
	public VerticalLayout(int vgap) {
		this(vgap, CENTER, TOP);
	}

	/**
	 * Constructs a VerticalLayout instance anchored to the top with the
	 * specified vgap and horizontal alignment
	 * 
	 * @param vgap
	 *            An int value indicating the vertical seperation of the
	 *            components
	 * @param alignment
	 *            An int value which is one of
	 *            <code>RIGHT, LEFT, CENTER, BOTH</code> for the horizontal
	 *            alignment.
	 */
	public VerticalLayout(int vgap, int alignment) {
		this(vgap, alignment, TOP);
	}

	/**
	 * Constructs a VerticalLayout instance with the specified vgap, horizontal
	 * alignment and anchoring
	 * 
	 * @param vgap
	 *            An int value indicating the vertical seperation of the
	 *            components
	 * @param alignment
	 *            An int value which is one of
	 *            <code>RIGHT, LEFT, CENTER, BOTH</code> for the horizontal
	 *            alignment.
	 * @param anchor
	 *            An int value which is one of <code>TOP, BOTTOM, CENTER</code>
	 *            indicating where the components are to appear if the display
	 *            area exceeds the minimum necessary.
	 */
	public VerticalLayout(int vgap, int alignment, int anchor) {
		this.vgap = vgap;
		this.alignment = alignment;
		this.anchor = anchor;
	}

	// ----------------------------------------------------------------------------
	private Dimension layoutSize(Container parent, boolean minimum) {
		Dimension dim = new Dimension(0, 0);
		Dimension d;
		synchronized (parent.getTreeLock()) {
			int n = parent.getComponentCount();
			for (int i = 0; i < n; i++) {
				Component c = parent.getComponent(i);
				if (c.isVisible()) {
					d = minimum ? c.getMinimumSize() : c.getPreferredSize();
					dim.width = Math.max(dim.width, d.width);
					dim.height += d.height;
					if (i > 0)
						dim.height += vgap;
				}
			}
		}
		Insets insets = parent.getInsets();
		dim.width += insets.left + insets.right;
		dim.height += insets.top + insets.bottom + vgap + vgap;
		return dim;
	}

	// -----------------------------------------------------------------------------
	/**
	 * Lays out the container.
	 */
	public void layoutContainer(Container parent) {
		Insets insets = parent.getInsets();
		synchronized (parent.getTreeLock()) {
			int n = parent.getComponentCount();
			Dimension pd = parent.getSize();
			int y = 0;
			// work out the total size
			for (int i = 0; i < n; i++) {
				Component c = parent.getComponent(i);
				Dimension d = c.getPreferredSize();
				y += d.height + vgap;
			}
			y -= vgap; // otherwise there's a vgap too many
			// Work out the anchor paint
			if (anchor == TOP)
				y = insets.top;
			else if (anchor == CENTER)
				y = (pd.height - y) / 2;
			else
				y = pd.height - y - insets.bottom;
			// do layout
			for (int i = 0; i < n; i++) {
				Component c = parent.getComponent(i);
				Dimension d = c.getPreferredSize();
				int x = insets.left;
				int wid = d.width;
				if (alignment == CENTER)
					x = (pd.width - d.width) / 2;
				else if (alignment == RIGHT)
					x = pd.width - d.width - insets.right;
				else if (alignment == BOTH)
					wid = pd.width - insets.left - insets.right;
				c.setBounds(x, y, wid, d.height);
				y += d.height + vgap;
			}
		}
	}

	// -----------------------------------------------------------------------------
	public Dimension minimumLayoutSize(Container parent) {
		return layoutSize(parent, false);
	}

	// -----------------------------------------------------------------------------
	public Dimension preferredLayoutSize(Container parent) {
		return layoutSize(parent, false);
	}

	// ----------------------------------------------------------------------------
	/**
	 * Not used by this class
	 */
	public void addLayoutComponent(String name, Component comp) {
	}

	// -----------------------------------------------------------------------------
	/**
	 * Not used by this class
	 */
	public void removeLayoutComponent(Component comp) {
	}

	// -----------------------------------------------------------------------------
	@Override
	public String toString() {
		return getClass().getName() + "[vgap=" + vgap + " align=" + alignment
				+ " anchor=" + anchor + "]";
	}
}
